A typical arrangement for the main landing gear of medium to large aircraft includes a telescopic shock absorbing landing gear strut pivotally connected to a bogie beam to which a number of axles and wheel pairs are mounted. In normal operation there is sufficient clearance between the bottom of the landing gear strut and the bogie beam to allow the bogie beam to rotate relative to the landing gear strut, for example during take-off and landing manoeuvres and optionally to aid stowage of the landing gear within the aeroplane when the landing gear is retracted.
However, in certain circumstances the bogie beam may be forced to rotate at a higher, than a normal rotation speed which in combination with the inertia of the bogie beam can lead to a greater degree of rotation than normal such that the bogie beam actually strikes the landing gear strut. To prevent damage to either the bogie beam or landing gear strut in the event of such impact between the bogie beam and strut it is known to provide one or more stop pads on the bogie beam such that in the event of over-rotation the stop pad strikes the landing gear strut rather than the bogie beam, thus avoiding any damage to the bogie beam itself. The material from which the stop pad is manufactured is selected so as to ordinarily be capable of withstanding a contact between the stop pad and the landing gear strut with minimal or no damage. Materials that have been used include aluminium and nylon. As the size of the landing gear, and thus in turn the bogie beam, increases the inertia of a rotating bogie beam increases correspondingly, which in turn increases the amount of energy that must be dissipated by the stop pad in the event of over-rotation of bogie beam causing the stop pad to strike the landing gear strut. Impacts between the stop pad and the landing gear strut above a certain energy will cause damage to the stop pad, requiring the stop pad to be replaced, and in more extreme circumstances may cause resulting damage to the bogie beam or landing gear strut themselves. There is clearly a physical limit to the size of stop pad that can be fitted, since the dimensions of the stop pad itself reduces the clearance between the bogie beam and landing gear strut.
There is therefore a problem to be addressed of absorbing the higher energies associated with the over-rotation of larger and heavier bogie beams.